You are walking on the beach when you step on a shell and cut your foot. Thirteen cells of Vibrio vulnificus bacteria are transferred from the shell and deposited deep inside the cut. 36 hours later, the cut has become extremely painful and you go to the doctor. If the generation time of this species is 90 minutes under these conditions
1a) How many bacteria are present at the time you go to the doctor?
Not realizing the severity of the infection and that he/she should use intravenous dual-drug antimicrobial therapy, the doctor prescribes only oral doxycycline and sends you home. At this time, the bacteria are not just in the wound. 29 cells of V. vulnificus have gotten into your blood. However, the doxycycline does slow the growth of the bacteria considerably to a generation time of 6 hours. Over the next few days, you take all of your doses of doxycycline, but become increasingly ill. Eventually, you collapse and are rushed to the hospital. It is determined that you have 7 cells/mL of bacteria in your blood. If you have 5 L of blood in your body,
1b) How many total bacterial cells are in your blood?
1c) How many generations have the bacteria been through from the time they entered your blood until you arrived at the hospital?
Because you are unconscious and the friend who brought you to the hospital does not know you were on oral doxycycline, the medical team that treats you initially does not realize that doxycycline is unlikely to be effective in fighting your infection because the bacteria have developed resistance to it. The usual treatment for V. vulnificus âsepticemiaâ would be an intravenous combination of doxycycline and a third-generation cephalosporin derivative. Five days after arriving at the hospital, your blood titer of bacteria is determined to be 19 cfu/mL. The generation time has slowed again due to the dual-drug treatment, but the bacteria are still growing. Using this new 19 cfu/mL titer, the titer given in the set-up for part b above, and the fact that this growth took 5 days, calculate the new slower generation time on the dual-drug treatment.
1d) What is the new generation time in hours?
The critical care medical team finally makes contact with your primary care physician and finds out that you had already been on oral doxycycline. Your critical care team decides to switch your treatment to intravenous ciprofloxacin. Soon after this treatment begins, the growth rate of the V. vulnificus becomes negligible due to the âbacteriostaticâ activity of ciprofloxacin. Given that the bacteria reached a titer of 21 cfu/mL in your blood before ciprofloxacin caused cessation of growth, if the death rate is 65% per day
1e) How many days of uninterrupted ciprofloxacin treatment would it take for the infection to clear?
You are walking on the beach when you step on a shell and cut your foot. Thirteen cells of Vibrio vulnificus bacteria are transferred from the shell and deposited deep inside the cut. 36 hours later, the cut has become extremely painful and you go to the doctor. If the generation time of this species is 90 minutes under these conditions
1a) How many bacteria are present at the time you go to the doctor?
Not realizing the severity of the infection and that he/she should use intravenous dual-drug antimicrobial therapy, the doctor prescribes only oral doxycycline and sends you home. At this time, the bacteria are not just in the wound. 29 cells of V. vulnificus have gotten into your blood. However, the doxycycline does slow the growth of the bacteria considerably to a generation time of 6 hours. Over the next few days, you take all of your doses of doxycycline, but become increasingly ill. Eventually, you collapse and are rushed to the hospital. It is determined that you have 7 cells/mL of bacteria in your blood. If you have 5 L of blood in your body,
1b) How many total bacterial cells are in your blood?
1c) How many generations have the bacteria been through from the time they entered your blood until you arrived at the hospital?
Because you are unconscious and the friend who brought you to the hospital does not know you were on oral doxycycline, the medical team that treats you initially does not realize that doxycycline is unlikely to be effective in fighting your infection because the bacteria have developed resistance to it. The usual treatment for V. vulnificus âsepticemiaâ would be an intravenous combination of doxycycline and a third-generation cephalosporin derivative. Five days after arriving at the hospital, your blood titer of bacteria is determined to be 19 cfu/mL. The generation time has slowed again due to the dual-drug treatment, but the bacteria are still growing. Using this new 19 cfu/mL titer, the titer given in the set-up for part b above, and the fact that this growth took 5 days, calculate the new slower generation time on the dual-drug treatment.
1d) What is the new generation time in hours?
The critical care medical team finally makes contact with your primary care physician and finds out that you had already been on oral doxycycline. Your critical care team decides to switch your treatment to intravenous ciprofloxacin. Soon after this treatment begins, the growth rate of the V. vulnificus becomes negligible due to the âbacteriostaticâ activity of ciprofloxacin. Given that the bacteria reached a titer of 21 cfu/mL in your blood before ciprofloxacin caused cessation of growth, if the death rate is 65% per day
1e) How many days of uninterrupted ciprofloxacin treatment would it take for the infection to clear?
